Most Recent Weekly Report: 26 August-1 September 2009

Based on analyses of satellite imagery, SVERT reported that on 26 August a gas-and-steam plume possibly containing ash rose from Berg (part of the Kolokol Group of volcanoes) to an altitude greater than 6 km (19,700 ft) a.s.l. and drifted NE.

Index of Weekly Reports

Weekly Reports

26 August-1 September 2009

Based on analyses of satellite imagery, SVERT reported that on 26 August a gas-and-steam plume possibly containing ash rose from Berg (part of the Kolokol Group of volcanoes) to an altitude greater than 6 km (19,700 ft) a.s.l. and drifted NE.

A group of Holocene volcanoes in central Urup Island is named after its most prominent volcano, Kolokol. Berg and Trezubetz volcanoes, flanking Kolokol on the NW, have breached summit calderas partially filled by lava domes. Trezubetz, whose name means "trident," has an eroded crater rim with three large peaks when seen at sea from the north. Kolokol volcano rises to 1328 m and is sometimes known as Urup-Fuji because of its symmetrical profile. The crater of Kolokol is not well preserved, but the volcano displays no evidence of glacial erosion. Several lava flows originate from Kolokol; one of these extends almost to the Sea of Okhotsk coast. A viscous lava flow armoring the SE flank is probably the most recent from Kolokol. Borzov volcano, the oldest of the group, lies to the SW of Kolokol. Eruptions of the Kolokol volcano group have been observed in historical time since the late-18th century. Berg volcano has been most active, but Trezubetz erupted in 1924.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Cones

Feature Name

Feature Type

Elevation

Latitude

Longitude

Berg

Somma volcano

1040 m

46° 4' 0" N

150° 5' 0" E

Borzov

Cone

Kolokol
Uruppu Fudzi
Urup-Fuji

Stratovolcano

1328 m

46° 3' 0" N

150° 3' 29" E

Trezubetz
Dzigoku
Jigoku Yama
Zigoku

Somma volcano

1220 m

46° 4' 0" N

150° 7' 0" E

Berg volcano, seen here from the SE, is part of a closely spaced group of Holocene volcanoes in central Urup Island that is named after its most prominent symmetrical volcano, Kolokol. Berg, which has a 2-km-wide caldera breached to the NW that contains a large lava dome, is the most recently active of the group. Steam rises from an explosion crater on the NW side of the 250-m-high lava dome and a prominent explosion crater (center) cuts its southern side. Eruptions of Berg have been documented since the late-18th century.

A steaming lava dome partially fills the breached summit caldera of Berg volcano, with conical Kolokol volcano in the background to the south. They are part of a group of Holocene volcanoes in central Urup Island that is named after its most prominent volcano, Kolokol. Berg and Trezubetz volcanoes, flanking Kolokol on the NW, have breached summit calderas partially filled by lava domes. Kolokol volcano rises to 1328 m and is sometimes known as Urup-Fuji because of its symmetrical profile.

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.

EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).